Thomas Wright (about 1686-1767) was a prominent London maker who had gone into
business for himself in 1718, after having learned the trade from John Rowley. He traded at the
sign of The Orrery & Globe, was appointed Mathematical Instrument Maker to His Royal
Highness, George, Prince of Wales, and produced "all sorts of Mathematical Instruments for Sea & Land According to the best & latest Improvements." The title of his royal appointment
changed in 1727, when George II ascended to the throne. Wright retired from business in 1748.
This elegant instrument has two open sights attached to the circle, and two on the alidade. The circle is graduated to degrees, and read by vernier to 5 minutes.
Ref: Gloria Clifton, Directory of British Scientific Instrument Makers 1550-1851 (London,
1995), p. 306.